package com.hmdp.service.impl;

import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.Shop;
import com.hmdp.entity.ShopType;
import com.hmdp.mapper.ShopMapper;
import com.hmdp.service.IShopService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.CacheClient;
import com.hmdp.utils.RedisData;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

import static com.hmdp.utils.RedisConstants.*;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class ShopServiceImpl extends ServiceImpl<ShopMapper, Shop> implements IShopService {

    @Autowired
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    CacheClient cacheClient;

    @Override
    public Result queryById(Long id) {
        //缓存穿透
        //Shop shop = cacheClient.queryWithPassThrough(CACHE_SHOP_KEY,id,Shop.class,id2->getById(id2),CACHE_SHOP_TTL,TimeUnit.MINUTES);
        //Shop shop = cacheClient.queryWithPassThrough(CACHE_SHOP_KEY,id,Shop.class,this::getById,CACHE_SHOP_TTL,TimeUnit.MINUTES);
        //互斥锁解决缓存击穿
        //Shop shop = queryWithMutex(id);

        //逻辑过期解决缓存击穿
        Shop shop = cacheClient.queryWithLogicExpire(CACHE_SHOP_KEY,id, Shop.class,LOCK_SHOP_KEY,this::getById,20L,TimeUnit.SECONDS);
        if (shop == null){
            return Result.fail("店铺不存在！");
        }
        //7.返回
        return Result.ok(shop);
    }

//    private static final ExecutorService CACHE_REBUILD_EXECUTOR = Executors.newFixedThreadPool(10);
//
//    public Shop queryWithLogicExpire(Long id){
//        String key = "cache:shop:" + id;
//        //1.从redis查询商铺缓存
//        String shopJson = stringRedisTemplate.opsForValue().get(key);
//        //2.判断是否存在
//        if (StrUtil.isBlank(shopJson)){
//            //3.不存在，直接返回
//            return null;
//        }
//        //4.命中，需要把json反序列化为对象
//        RedisData redisData = JSONUtil.toBean(shopJson, RedisData.class);
//        Shop shop = JSONUtil.toBean((JSONObject) redisData.getData(),Shop.class);
//        LocalDateTime expireTime = redisData.getExpireTime();
//        //5.判断是否过期
//        if (expireTime.isAfter(LocalDateTime.now())){
//            //5.1 未过期，直接返回店铺信息
//            return shop;
//        }
//        //5.2 过期，需要缓存重建
//        //6.缓存重建
//        //6.1 获取互斥锁
//        String lockKey = "lock:shop:"+id;
//        boolean isLock = tryLock(lockKey);
//        //6.2 判断是否获取锁成功
//        if (isLock){
//            //6.3 成功，开启独立线程，实现缓存重建
//            CACHE_REBUILD_EXECUTOR.submit(()->{
//                try {
//                    //重建缓存
//                    this.saveShop2Redis(id,20L);
//                } catch (Exception e) {
//                    throw new RuntimeException(e);
//                }finally {
//                    //释放锁
//                    unlock(lockKey);
//                }
//            });
//        }
//        //6.4 失败返回过期的店铺信息
//        return shop;
//    }
//
//    public Shop queryWithMutex(Long id){
//        String key = "cache:shop:" + id;
//        //1.从redis查询商铺缓存
//        String shopJson = stringRedisTemplate.opsForValue().get(key);
//        //2.判断是否存在
//        if (StrUtil.isNotBlank(shopJson)){
//            //3.存在，直接返回
//            return JSONUtil.toBean(shopJson, Shop.class);
//        }
//        //判断命中的是否是空值
//        if (shopJson!=null){
//            //返回错误信息
//            return null;
//        }
//        //4.开始实现缓存重建
//        //4.1 获取互斥锁
//        String lockKey = "lock:shop:"+id;
//        Shop shop = null;
//        try {
//            boolean isLock = tryLock(lockKey);
//            //4.2 判断是否获取成功
//            if (!isLock){
//                //4.3 失败，则休眠并重试
//                Thread.sleep(5);
//                return queryWithMutex(id);
//            }
//            //4.4不存在，根据id查询数据库
//            shop = getById(id);
//            //模拟重建的延迟
//            Thread.sleep(200);
//            //5.不存在，返回错误
//            if (shop == null){
//                //将空值写入redis
//                stringRedisTemplate.opsForValue().set(key,"",CACHE_NULL_TTL,TimeUnit.MINUTES);
//                //返回错误信息
//                return null;
//            }
//            //6.存在，写入redis
//            stringRedisTemplate.opsForValue().set(key,JSONUtil.toJsonStr(shop),30L, TimeUnit.MINUTES);
//        } catch (Exception e) {
//            throw new RuntimeException(e);
//        }finally {
//            //7.释放互斥锁
//            unlock(lockKey);
//        }
//        //8.返回
//        return shop;
//    }
//
//
//    public Shop queryWithPassThrough(Long id){
//        String key = "cache:shop:" + id;
//        //1.从redis查询商铺缓存
//        String shopJson = stringRedisTemplate.opsForValue().get(key);
//        //2.判断是否存在
//        if (StrUtil.isNotBlank(shopJson)){
//            //3.存在，直接返回
//            return JSONUtil.toBean(shopJson, Shop.class);
//        }
//        //判断命中的是否是空值
//        if (shopJson!=null){
//            //返回错误信息
//            return null;
//        }
//        //4.不存在，根据id查询数据库
//        Shop shop = getById(id);
//        //5.不存在，返回错误
//        if (shop == null){
//            //将空值写入redis
//            stringRedisTemplate.opsForValue().set(key,"",CACHE_NULL_TTL,TimeUnit.MINUTES);
//            //返回错误信息
//            return null;
//        }
//        //6.存在，写入redis
//        stringRedisTemplate.opsForValue().set(key,JSONUtil.toJsonStr(shop),30L, TimeUnit.MINUTES);
//        //7.返回
//        return shop;
//    }
//
//    private boolean tryLock(String key){
//        Boolean flag = stringRedisTemplate.opsForValue().setIfAbsent(key, "1", 1, TimeUnit.MINUTES);
//        return BooleanUtil.isTrue(flag);
//    }
//
//    private void unlock(String key){
//        stringRedisTemplate.delete(key);
//    }
//
//
//    public void saveShop2Redis(Long id,Long expireSeconds) throws InterruptedException {
//        //1.查询电批数据
//        Shop shop = getById(id);
//        Thread.sleep(200);
//        //2.封装过期时间
//        RedisData redisData = new RedisData();
//        redisData.setData(shop);
//        redisData.setExpireTime(LocalDateTime.now().plusSeconds(expireSeconds));
//        //3.写入redis
//        stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY+id,JSONUtil.toJsonStr(redisData));
//    }

    @Override
    @Transactional
    public Result update(Shop shop) {
        Long id = shop.getId();
        if (id == null){
            return Result.fail("店铺id不能为空");
        }
        //1.更新数据库
        updateById(shop);
        //2.删除缓存
        stringRedisTemplate.delete(CACHE_SHOP_KEY+shop.getId());
        return Result.ok();
    }
}
